Impact of silica porosity on the catalytic activity of nanosize gold catalyst for CO oxidation

Series of nanosize gold catalysts supported by three kinds of silica with different structures were prepared by deposition-precipitation.The CO oxidation was utilized as a probe.The impacts of silica on the structure and catalytic activity were characterized by low-temperature N₂ adsorption/desoprtion,X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),and transmission electron microscope (TEM).The result turns out that the relationship between the gold nanopaticle size and the support’s structure does exist.The higher surface area and the smaller pore size of the silica support corresponding to a smaller gold nanoparticle size and higher activity of CO oxidation.The total CO conversion under 18 000 mL/(h·g_cat) with gas ratio of v(CO)/v(O₂)/v(Ar)=1/21/78 is 560 K.